What is Cholesterol?

Cholesterol is a molecule found in foods and also produced in our own bodies. This molecule is essential for normal bodily function, but too much can be bad. Over the past few decades we have learned that high levels of cholesterol can significantly increase the risk of heart disease and stroke by forming plaques that block and damage arteries. More importantly, we have discovered that we can dramatically reduce the risk of developing these diseases in many people if we reduce their cholesterol levels.

Why is my Cholesterol level high?

The cholesterol which is found in our bodies comes from two sources. Some cholesterol comes directly from our diet. While some foods have no cholesterol, others have very high amounts. If your cholesterol level is high, it is important to pay attention to the cholesterol content of foods that you eat. It is also important to pay attention to the fat content and the type of fats found in the food you eat since certain fats, especially saturated fats and trans-fats can be more easily converted to cholesterol by the body. Much of the cholesterol in our bodies is in fact manufactured from these fats. Cholesterol is produced through a series of chemical reactions and the rate at which these reactions occur is controlled by several "enzymes". Enzymes are proteins in our bodies which can speed up the rate at which a reaction takes place. We all inherit slightly different versions of these enzymes. The result is that some of us produce a lot of cholesterol, and others produce much less. Many of the most frequently prescribed cholesterol medications work by inhibiting one of these enzymes and slowing down the production of cholesterol by the body.

What is "Good and Bad" Cholesterol?

You may have heard the terms "Good" and "Bad" cholesterol before. Although we call them good and bad "cholesterol" the actual cholesterol molecule ( see image at top of page) in good and bad cholesterol is exactly the same. What the term good and bad really refer to are the "packages" or particles that contain the cholesterol as it is transported through our blood stream. Each particle has cholesterol in the center surrounded by a fatty membrane within which float a series of protein molecules. HDL and LDL particles each contain the same cholesterol molecules in the center but the various proteins on the surface of the package make them different and it is these proteins that determine whether the particle will increase or decrease the formation of plaques in the artery wall. Chylomicrons are particles that carry a mixture of Triglycerides and cholesterol in their center. For the sake of simplicity we simply refer to these particles as triglycerides.

Think of the Tryglycerides and LDL's as the "litter bugs". They travel through the blood stream and leave cholesterol deposits along the arteries which increase inflammation and lead to the development of plaques. Plaques can gradually clog an artery. Plaques can and often do cause heart attacks even before they are large enough to block the artery. If there is an increased level of inflammation in a plaque it can become unstable. When this happens it may rupture and trigger the formation of a clot within the blood vessel which can suddenly block blood flow through an artery and cause a heart attack or stroke. In fact most heart attacks occur as a result of plaques that are relatively small but unstable. HDL then is like the "sanitation crew". It travels through the blood stream also, but it picks up cholesterol from those deposits and reduces inflammation in plaques. Ideally you want your LDL and Triglyceride as low as possible and your HDL as high as possible.

The cholesterol number that most people are familiar with is the Total Cholesterol. The Total Cholesterol is actually the sum of all the good and bad cholesterol numbers using the following formula.

TOTAL CHOLESTEROL = HDL + LDL + ( 0.2 x Triglycerides)

HDL - Good cholesterol
LDL - Bad Cholesterol
Triglycerides ( Found in Chylomicrons) - Also bad but doesn't affect risk as much as LDL

The total cholesterol is not as important as the individual numbers and is not used as a guide for treatment because an increase in HDL which is desirable, will make the total go up. Generally we ignore the total cholesterol and make treatment decisions based on the HDL, LDL, and Triglyceride numbers.

What should my numbers be?

HDL - Should be more than 40Triglycerides - Should be less than 150LDL - Less than 190. Diabetics and patients with a history of heart disease or stroke should keep their LDL less than 100.

Who should be treated with Statins?

New guidelines from the American Heart Association and the American Cardiology Association which were announced 11/12/13 recommend that the following people should be considered for statin therapy

All people who are diabetic

People with an LDL over 190

People with a prior history of atherosclerotic cardiovascular disease (ASCVD)*

* ASCVD refers to the disease process that leads to the formation of plaque in arteries throughout the body increasing the risk of heart attack and stroke. This includes patients with a prior history of heart attack or stroke.

What can I do if my numbers aren't what they should be?

What you do about your numbers depends on what is wrong. Are your HDL's too low? Is your LDL level too high or is it your Triglycerides?

Medications like statins when levels can not be controlled with lifestyle changes.

Control your other cardiovascular risk factors like High Blood Pressure, Diabetes, Obesity, Smoking

How do cholesterol medicines work?

The cholesterol in our body comes from two places. There is cholesterol in the foods we eat and also cholesterol that our bodies manufacture.

The most common cholesterol medications are the "statins" like Zocor, Lipitor, Pravachol, and Crestor. These drugs inhibit an enzyme known as HMG-CoA Reductase which normally promotes and important step in cholesterol production. By inhibiting this enzyme they slow down the production of cholesterol. These medicines also have an anti-inflammatory effect that reduces the formation of plaque in our arteries.

Other cholesterol medications such as Zetia reduce absorption of cholesterol in the intestines. This medicine does not have the same anti-inflammatory effect that statins do and has not been shown to reduce the risk of cardiovascular to the same degree.